Zebra Caterpillars

There have been a few reports of zebra caterpillars feeding on some vegetable crops. This caterpillar is considered to be a minor nuisance pest on vegetable crops. Zebra caterpillars have a broad host range and will feed on several vegetable plants and weeds across southern Canada and northern US. Across this range there could be two generations of per year, with the first occurring in June-July and a second in August-October; however, little is known about the life cycle of this pest in Ontario.

The moth is a brownish, non-descript moth with a wingspan of ~2 cm. The female lays its eggs in clusters. The eggs hatch all at once and the larvae swarm all over the leaf surface (Figure 1).

Figure 1. Zebra caterpillar eggs hatch all at once and the larvae swarm all over the leaf surfaceFigure 2. Small larvae make small holes and skeletonise foliage, while larger larvae will eat large holes in foliage

Zebra caterpillar larvae are the destructive life stage. The larvae defoliate leaves through feeding. Small larvae make small holes and skeletonize foliage, while larger larvae will eat large holes in foliage (Figure 2).

Mature larvae have distinct yellow, black and white markings (Figure 3). Yellow and white stripes separated by ‘zebra’ striping run along the side of the larva. The underside is orange. Young larvae tend to feed in groups. They are green or dark coloured and can be difficult to distinguish from other types of caterpillars.

Infestations are typically sporadic and random and usually do not warrant control measures. Remove infested plant material and destroy larvae.